Combined defects in epithelial and immunoregulatory factors exacerbate the pathogenesis of inflammation: mucin 2-interleukin 10-deficient mice

Lab Invest. 2008 Jun;88(6):634-42. doi: 10.1038/labinvest.2008.28. Epub 2008 Apr 21.

Abstract

Expression of the mucin MUC2, the structural component of the colonic mucus layer, is lowered in ulcerative colitis. Furthermore, interleukin (IL)-10 knockout (IL-10-/-) mice develop colitis and have reduced Muc2 levels. Our aim was to obtain insight into the role of Muc2 and IL-10 in epithelial protection. Muc2-IL-10 double-knockout (Muc2/IL-10(DKO)) mice were characterized and compared to Muc2 knockout (Muc2-/-), IL-10-/- and wild-type (WT) mice. Clinical symptoms, intestinal morphology and differences in epithelial-specific protein levels were analyzed. In addition, levels of the pro-inflammatory cytokines in colonic tissue and serum were determined. IL-10-/- mice were indistinguishable from WT mice throughout this experiment and showed no clinical or histological signs of colitis. Muc2/IL-10(DKO) and Muc2-/- mice showed significant growth retardation and clinical signs of colitis at 4 and 5 weeks, respectively. Muc2/IL-10(DKO) mice had a high mortality rate (50% survival/5 weeks) compared to the other types of mice (100% survival). Microscopic analysis of the colon of Muc2/IL-10(DKO) mice showed mucosal thickening, increased proliferation, superficial erosions and a diminished Muc4 expression. Furthermore, pro-inflammatory cytokines were significantly upregulated, both in tissue (mRNA) and systemically in Muc2/IL-10(DKO) mice. In conclusion, Muc2/IL-10(DKO) mice develop colitis, which is more severe in every aspect compared to Muc2-/- and IL-10-/- mice. These data indicate that (i) in case of Muc2 deficiency, the anti-inflammatory cytokine IL-10 can control epithelial damage, though to a limited extent and (ii) the mucus layer is most likely a key factor determining colitis.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Colitis / metabolism
  • Colitis / pathology
  • Colon / metabolism
  • Colon / pathology
  • Cytokines / blood
  • Cytokines / metabolism
  • Disease Models, Animal
  • Epithelium / immunology*
  • Epithelium / pathology
  • Heterozygote
  • Immunohistochemistry
  • Immunologic Factors / metabolism*
  • Inflammation / etiology*
  • Inflammation / pathology
  • Interleukin-10 / deficiency*
  • Interleukin-10 / genetics
  • Intestinal Mucosa / metabolism
  • Intestinal Mucosa / pathology
  • Mice
  • Mice, Knockout
  • Mucin-2
  • Mucins / deficiency*
  • Mucins / genetics

Substances

  • Cytokines
  • Immunologic Factors
  • Muc2 protein, mouse
  • Mucin-2
  • Mucins
  • Interleukin-10